Multistage amplifier circuits, including those with degenerative feedback, have been employed for a variety of signal processing applications, from audio amplifier circuits to high performance, wideband RF systems. In the former case, the fundamental design criterion usually involves the requisite gain, coupled with the need for minimum loading (high input impedance) and maximum follow-on stage coupling (low output impedance). In high frequency signal environments, such as VHF, UHF and other wideband RF signal applications, additional parameters, such as low-distortion, interface (e.g. 50 ohm) impedance matching, and high reverse isolation constitute critical performance considerations. In a conventional multistage amplifier circuit employing common-emitter transistors, feedback is customarily realized through D.C. coupling networks from the output stage to the input stage, which inherently limits the degree of reverse isolation that is obtainable.